Model output discussion - into the last third of January

[sheikhy]

Back down to earth on the 00z again?!!any improvements at 144 hours on the big 3?!!has gfs moved towards ukmo and has ukmo dropped the snow event for saturday?!!any snowy surprises between now and tuesday?!!not really interested at whats happening after the next 6 days lol!!

[Frosty.]

Morning all,

The way I see it, there is currently no way we will avoid a milder period during the second half of of next week according to the 0z output, and I’m not saying this in a pessimistic way, just being realistic based on what I’m seeing, even Scotland would become milder too...how long would it last?..well, the GEFS 0z mean does indicate a colder trend during early Feb?

[mb018538]

5 minutes ago, sheikhy said:

Back down to earth on the 00z again?!!any improvements at 144 hours on the big 3?!!has gfs moved towards ukmo and has ukmo dropped the snow event for saturday?!!any snowy surprises between now and tuesday?!!not really interested at whats happening after the next 6 days lol!!

 

ECM still has the low running across the south Sunday with potential for a period of snow. Not much else!

[IDO]

8 hours ago, bluearmy said:

Do we assume that the other three gfs runs that day were with a greeny ridge and the para ones were not - wouldn’t be right to pick the worst example so will assume that you didn’t .......

My point was not that the para is not better, it is, the issue is that it has runs which stray from the standard deviation so far that there must be some inherent algorithmic error to produce these 0.1, 02 and 0.3 at d10? Surely these have to be resolved before it is stable enough for general consumption?

I did do the latest data I had, the 12z and I looked at no other run as it proved the point I was making, and also pointed out it may be "bad luck" happenstance but it highlights my concerns about this going on-stream.

No surprise it has corrected itself this morning from last night's 18z;  d8:

[That ECM]

7 minutes ago, mb018538 said:

 

ECM still has the low running across the south Sunday with potential for a period of snow. Not much else!

Parts of Scotland are in an Amber warning for snow now. I think ecm fi is still looking interesting.

[SLEETY]

The deep cold is back in lala land, on gfs (P) so   only around  20 more runs just  to see it get towards the semi-reliable timeframe ,still at least its been consistent at that timeframe for a change.

What could go wrong.. 

[Griff]

11 minutes ago, IDO said:

My point was not that the para is not better, it is, the issue is that it has runs which stray from the standard deviation so far that there must be some inherent algorithmic error to produce these 0.1, 02 and 0.3 at d10? Surely these have to be resolved before it is stable enough for general consumption?

I did do the latest data I had, the 12z and I looked at no other run as it proved the point I was making, and also pointed out it may be "bad luck" happenstance but it highlights my concerns about this going on-stream.

No surprise it has corrected itself this morning from last night's 18z;  d8:

First time the ECM has even remotely echoed anything vaguely similar. 

I appreciate its day 10 reputation, but given how much time this thread devotes to gfs in FI, I suspect FI is where changes will start to show up. 

No expectations but things to keep an eye on, in lieu of anything more interesting in the reliable or near term. 

Edited January 21, 2021 by Griff

[Duane S.]

Nothing to fret about whatsoever having looked at the 00z suite. No wholesale changes, it’s pretty much as we were.

A lot of snow for many Northern areas ongoing, a few days of interest coming up for those further south, then a well forecast warmup that will likely take us towards  the end of the month. Then, that is where things could start to get interesting again. Continuing  signs of a scandi / Icelandic high forming as we head into February. GFS OP not really interested on this run.

ECM messy but I can see an easterly a short while later from this...

 

GFSP has been resolute for a few runs, bar one, recently...

The GEM bring it in very early. Unlikely IMO but maybe one to watch?...

 

[Tim Bland]

GEM goes for the wedge ...

[IDO]

2 minutes ago, Griff said:

First time the ECM has even remotely echoed anything vaguely similar. 

I appreciate its day 10 reputation, but given how much time this thread devotes to gfs in FI, I suspect FI is where changes will start to show up. 

No expectations but things to keep an eye on,in lieu of anything more interesting in the reliable or near term. 

I agree, once we move into Feb there should be changes, and the wedges into higher latitudes to our NW/N/NE have been showing up regular. However, mostly they appear fleeting when they do on the gefs, so I am not convinced they will go anywhere useful.

During the 16 days on the gefs two Pacific-wave wedges develop towards the Arctic but both tend to stay on the other side of the NH which is a worst case scenario. d13 mean for example:

I am only looking at the bigger picture, not the slings and arrows of micro-scale features, looking for a sea-change to a wintry sustained cold spell. There can still be wintry mixes but the overall pattern post d9 isn't great atm, but it remains fluid with lots of uncertainty as we hit Feb.

[Radiating Dendrite]

3 minutes ago, Vikos said:

This is not adequate, sorry. One should keep the spitefulness out. It leads to nothing...

Exactly the reason why I have blocked this member. It could show a raging blizzard at +24 and he would still be moaning about something. 

It is the model thread, so we can discuss whatever model or timeframe we wish to and draw our own conclusions. If people want to go back to the ceefax days and just see things two days in advance then stick to the met site and stop viewing this thread. 

Anyway, I'm fairly optimistic. A couple of possible snow chances the next few days and then a short milder spell next week before things could start getting colder again from next weekend. A couple of models keep showing an Easterly in early feb as a possibility, with the ECM for to hit this range soon....so it will be interesting to see if we see tentative signs from this model as well. Could be similar to 2018, once it showed and all models picked up, we gradually counted it down with only a few hiccups thrown in. 

[Griff]

1 minute ago, IDO said:

I agree, once we move into Feb there should be changes, and the wedges into higher latitudes to our NW/N/NE have been showing up regular. However, mostly they appear fleeting when they do on the gefs, so I am not convinced they will go anywhere useful.

During the 16 days on the gefs two Pacific-wave wedges develop towards the Arctic but both tend to stay on the other side of the NH which is a worst case scenario. d13 mean for example:

I am only looking at the bigger picture, not the slings and arrows of micro-scale features, looking for a sea-change to a wintry sustained cold spell. There can still be wintry mixes but the overall pattern post d9 isn't great atm, but it remains fluid with lots of uncertainty as we hit Feb.

It's a confusing and unclear big picture, that's for sure. A lot has already been mentioned this week about teleconnections, MJO etc. 

What's hard to factor and far from settled is strat / trop impacts, given that they remain ongoing. Zonal winds are forecast to reduce and briefly return to negative once more at the start of February. Fascinating how this will impact and overlap with the model runs, which is what I think should be looked out for in FI. 

Likewise I'm looking for larger changes, rather than dissecting a shortwave or precipitation chart at day 10

[Vikos]

Maybe it's just a feeling, but could it be that the models swing at shorter intervals? Is it a background signal that has a massive impact on the prognosis? MJO?

   

 

   

 

FI is (more hope than knowledge) Around 72/96hr

[nick sussex]

A growing signal this morning for a return to milder conditions from the big 3 especially away from areas much further north .

Timeframe varies slightly with the UKMO quicker , however its day 4 output isn’t supported in terms of that shortwave trying to push east and given its recent performance the consensus is more  day 6 than 5 .

Post day 6 a varied range of solutions from the more interesting GEM , the ECM repeats its day ten from last night with a strong build of heights into the Arctic from the Pacific side , if that chart was within the more reliable it certainly has potential , potential however seems to be how much of the winter has played out !

In terms of any breakdown day 5/6  this still has the potential to have some snow, the models do differ with how that occurs and how quickly .

Its hard though to see the Azores high being denied at this point which wants to ridge ne in response to the upstream trough set up .

There’s a bit more uncertainty further north where there is some support for the colder air hanging on a while longer , if the Azores high isn’t to claim victory changes need to happen ASAP as in starting with this afternoons outputs ! 

In terms of how long any milder conditions might last there is still uncertainty over how much impact the MJO might have on proceedings .

Any previous forecasts have mistaken the La Niña footprint for an increase in the MJO signal , forecasters at NCEP are a bit more confident this time though  that the latest forecasts do represent a truer MJO.

So I think the best starting point in terms of base expectations moving forward .

Now to day 5 , a wintry mix , a risk of a more prolonged spell of snow moving east on Sunday .

Day 5 to 6 , breakdown , slower in the north , potential snow as that happens more especially for those areas .

Day 7 to 9 a return to milder conditions . Small chance of the cold hanging on in the far north .

Day 10 to day 14 ? Lots of uncertainty which is normally the case but more so now given the MJO and continued effects of the SSW .

 

[IDO]

Just with regard to the d10 gem and it is a clear outlier (with another member). The control has +10c uppers in Manchester when the op has -8c>

op> mean>

 

manchester>

Also, the ecm is a statistical outlier for pressure at d9 and even as early as d5 is outside standard deviation (just). Would need more runs to think along its evolution lines and atm probably one run to treat with caution?

[Kentspur]

MJO looks even better, a higher amplitude today looking at GFS ECM and CFS forecasts phase 7 more likely than 6? Isn't this better for blocking than 6? Anyone care to explain the main differences in terms of pressure pattern/ forcing

Edited January 21, 2021 by Kentspur

[Blessed Weather]

5 minutes ago, Kentspur said:

MJO looks even better, a higher amplitute today looking at GFS ECM and CFS forecasts phase 7 more likely than 6? Isn't this better for blocking than 6? Anyone care to explain the main differences in terms of pressure pattern/ forcing

Makes a big difference:

Phase 6 Nina:   Phase 7 Nina:

Source: https://www.meteonetwork.it/models/mjo/

[IDO]

15 minutes ago, Kentspur said:

MJO looks even better, a higher amplitute today looking at GFS ECM and CFS forecasts phase 7 more likely than 6? Isn't this better for blocking than 6? Anyone care to explain the main differences in terms of pressure pattern/ forcing

 

Worth remembering the MJO signal has been subdued due to the La Nina background so we shall have to see if the current forecasts are likely to land. NCEP in their latest MJO update: 

RMM forecasts are often influenced by the low frequency La Niña signal, which can result in them incorrectly predicting strong MJO events.
• This has been the case during the past several weeks and will remain a concern throughout the duration of the La Niña event, which means we are likely to have reduced confidence in MJO forecasts during this time.

source > here <

[Purga]

GEM is interesting and in fact is slightly outperforming the other models recently

 

 

 

Edited January 21, 2021 by Purga

[Kentspur]

Just now, Purga said:

There's some rather sexy snow spikes showing on the London GEFS

 

I think the Mods ought to censor this type of thing.

I've been posting these in the SE thread the trouble is the mean is offering barely a dusting its only really a few stray ensembles but good to think optimistically

[Vikos]

13 minutes ago, IDO said:

Worth remembering the MJO signal has been subdued due to the La Nina background so we shall have to see if the current forecasts are likely to land. NCEP in their latest MJO update: 

RMM forecasts are often influenced by the low frequency La Niña signal, which can result in them incorrectly predicting strong MJO events.
• This has been the case during the past several weeks and will remain a concern throughout the duration of the La Niña event, which means we are likely to have reduced confidence in MJO forecasts during this time.

source > here <

Does this also apply to the EC MJO? It looks a bit more conservative without so many outliers then GFS

Phase 7 is preferred

Edited January 21, 2021 by Vikos

[Grumpy Yorkshireman]

Morning all

Fabulous weather last night and we all got a shock with the west side ( I have two engineers stuck over there currently!)..... This why weather is so fascinating. Our local forecast here in Leeds last night has a coldish but dry weekend and I am looking at your Sunday charts with snow on them.

Keep up the great forecasting and, while there is so much uncertainty past 3 to 5 days, isn't that what makes it fun to ponder what could be based on experience. From what I am reading on here and from Judah Cohen, we just don't know for certain and the "Nailed on" I saw earlier  might have to sit on the shelf for a few weeks yet!

Roll on the next chapter 'cause I don't think we are finished with any extreme ....... As I said before, great site and effective moderators ... even for grumpy Yorkshiremen!!  

[Vikos]

Seems there is a massive drop predicted in the northern hemisphere for the end of that month

[Grumpy Yorkshireman]

For us less well qualified folks.... or just me, Can you explain that chart Vikos Please?

[Vikos]

1 minute ago, Grumpy Yorkshireman said:

For us less well qualified folks.... or just me, Can you explain that chart Vikos Please?

It's another effect of the stratospheric development that can be seen. The temperature anomaly of the entire northern hemisphere experiences a real crash, which means that the temperatures on the continents are falling. This is no accident, so there are reasons. And this is even so as GFS has a real warm BIAS.